To say, as a legislator, "I'm flattered that you are so interested in my vagina" – in the context of a Michigan legislative debate – is the perfect provocative sentence. And the storm that followed made the Michigan state courthouse the hottest place in the Midwest. But what was so incredibly bracing was the way in which Brown's provocation – and the Republican response to it – laid bare, so to speak, what the real power struggle is. The issue is not about obscenity, of course: it is about political control.

Brown, with strategic audacity, insisted that she was kept from the statehouse debate because of censorship around the word "vagina". House Republicans denied that this was the reason. They claimed something even more crazy, and more interesting: that it was her comparison of anti-abortion legislation to rape that led her – properly, in their view – to be barred, because, as they put it, the language she used was itself an act of chaos, disrupting proceedings. GOP Representative Lisa Posthumus Lyons, of Alto, said in a statement last week:

"Her comments compared the support of legislation protecting women and life to rape, and I fully support majority floor leader Jim Stamas' decision to maintain professionalism and order on the House floor."

Brown understands her moment, and that the best defense is a great offense. Female liberals understand that when you enrage the opposition, you don't back down; you go further. She staged a reading of "The Vagina Monologues" on the Michigan courthouse steps: 2,500 people, men and women, came to watch Brown, along with an appearance by revered playwright and rape campaigner Eve Ensler. (See this account from Autumn Smith.)

Making the V-sign in Lansing. Photograph: Autumn Smith

Ensler rightly pointed out that the issue is not about the propriety of the word, but about anxieties about women's access to power. Ensler declared, to applause:

"The vaginas are out. We are here to stay."

This battle fascinates me. I had a similar feeling watching a recent news item concerning Carol Price, a former TSA worker, who had experienced, going through security, what she thought was an overly invasive search. She turned to a supervisor and grabbed at the TSA agent's genitals to demonstrate, and was promptly arrested for "assault". This exchange, like the one in Michigan, suddenly snaps one out of the weird collective hypnosis of how "the way things are done" can make you not see the crazy-obvious. The TSA can grab your crotch and it's essential for "national security", but when you grab theirs, it's assault?

Legislators discussing at length and in detail bills dealing with women's vaginas and uteruses, and closely defining a legal range of vaginal options (for example, regarding ultrasound probes) – with outcomes sometimes profoundly against women's will about what should be done to their vaginas – is "legislative decorum"; but the minute a woman utters the word "vagina" or compares to being raped a planned legislative outcome against women's will, all hell breaks loose?

Something worth foregrounding, because it is so often obscured by debate about what happens in the uterus, is that D-and-C's and even later abortions are performed vaginally – that most private of private places, site of the most personal of decisions. What occurs in the Michigan statehouse when legislating on these issues is, therefore, categorically about Brown's vagina. I think Brown used that personal, intimate, confrontational word partly to demonstrate mnemonically how very personal, intimate and, literally, inward or internal the decision to have an abortion really is, and what the action of an abortion really involves.

The "pro-lifers", I have argued before, are entirely within their rights to hold up signs that show images of the fact of a dead fetus. It is a real fact, a real image, not propaganda or spin. But in exactly the same way, Brown is within her rights to shove the word "vagina" and even its image into the public discourse: it is an equally real fact, the real site where the result of all this wilful abstraction, in which the Michigan Republicans have sought to engage, will be played out. From a pro-life perspective, and from many points of view, there is no escape from the outcome being that so-graphic one. But from a pro-choice perspective, and others', too, there is no escape from the site of the abortion being that so-intimate one.

Brown's fight is not new. The 1970s were the high point of feminists waving the vagina flag in the hallowed halls of patriarchy. Indeed, the vagina has been contested linguistic and physical real estate for all of recorded patriarchy. But Brown's invocation – in the context of this new front in the "war on women" of copycat legislation focused on vaginas, similar to Michigan's, rolling out across 22 states – takes the fight to a new level.

The confrontation in Michigan confirms what Ensler makes clear: this is not about a sex organ, or about obscenity. The vagina isn't outrageous when it is under someone else's control, but it immediately becomes outrageous when a woman decides to control its meanings, define the morality and hermeneutics of its experiences – as Brown was doing – and determine its deployment, for herself. This fight beautifully illustrates what is so magical, disruptive and potent about the word "vagina" and vaginal politics.

Brown's was an act of appropriation. When "fags" became "queer" (as in the slogan, "we are here; we are queer"), they became more powerful, claiming that epithet and refusing the stigma and shame society had previously attached to it. Brown did the same thing.

I am not surprised that Brown's flag-waving is unleashing a torrent of female solidarity. This seems to be the year of the vagina; from virginity exams by the Egyptian military of female protesters in Tahrir Square, to the brutal introduction of the punitive transvaginal sonogram, women are being targeted in this age-old way. But what is new is that women are claiming the word, loud and clear. They have stopped running from the slut-shaming that so closely follows it; they have had enough of this kind of control and assault.

Liz Topp, co-author of Vaginas: A Owner's Manual, once described how, when a group of high-school girls realized how they were being disempowered and silenced, both sexually and socially, they asked for space in the school's meeting agenda, and, before the whole student body, stood side by side and shouted, "VAGINA! VAGINA! VAGINA!" They were, in their own way, saying no to the abuse and objectification of women, and taking back what was theirs.

As Lisa Brown and all the Michigan citizens who rallied around her have done.